Hi all. I have been culturing human PBMC and this is the first time i have seen some weird particles in my culture. I am attaching the photograph. Hopefully some of you may be able to identify the 'contaminants' (or not) for me. I have labelled some of the cells. Labelled A should be the red blood cells and D is the clump of lymphocytes (as i have activated them with PHA).

What i can't identify is B, C, E, F, G and H.

G seems to be a clump of cells smaller than the lymphocytes. Is B and H yeast? E seems to be an adherent cell. The smaller particles like C and F seems to vibrate but they are too big to be bacteria. Any ideas? Thanks.

-Ellyphant-

ermmmmm......Is your media cloudy at all, If I had to guess

D- looks like a clump of cellsE- looks like some cells, maybe about to undergo apoptosisA, B, C, F, H- cell debrisG- cells with some cell debris

D and G are possibly fungal in nature, but I can't see any hyphae so I'm not sure its contamination, could just be balling of the cells. Are you cells primary cells? Do you know if they are reaching the end of usuable passage numbers, maybe you're getting an increase in cell death as a result? Your description of vibrating- is it against the normal movement of particles? as in Not Brownian motion as that usual an indication of the particles being bacteria rather than debris. If you suspect any contamination, the best idea is to start with fresh cells and media- it doesn't really matter what the contamination is (unless its continual long term- they it might help you track down whats causing it).

If you're media is very cloudy and changed colour then suspect contaminationL Let us know if it is.